Use the multiplier when no BPM entry is needed
This page is for direct rehearsal and listening control. Move below normal speed to inspect a phrase or above normal speed to audition a faster pass; the current multiplier stays visible next to the control.
Preserved pitch and tape-style playback are explicit
Keep Preserve pitch on when you want the same musical key at a different tempo. Turn it off when the desired effect is coupled speed and pitch, as with changing tape or record speed.
A/B checking stays simple
Return the slider to normal speed for the source feel, then move back to the chosen multiplier. Because playback uses the same local file, no upload delay or server-rendered copy sits between comparisons.
Questions
These answers cover privacy, quality boundaries, and file support.
Does the tool export a processed file?
No. This page is a local playback tool; it does not claim to render a new file.
Can time stretching create artifacts?
Browser pitch compensation can sound less natural at large tempo changes, especially on dense mixes and exposed vocals.
What happens when I clear the page?
Playback stops and the temporary object URL is revoked.
Sources used for tempo behavior
The implementation follows HTMLMediaElement playbackRate and preservesPitch as documented by MDN and the HTML standard; the page states its local preview boundary directly.
Live microphone or selected-file audio is processed locally in this browser and is not uploaded.